The invention relates to a portion pack in the form of a tubular sleeve, in particular sausages, filled with a filling varying from small pieces to a paste and sealed at the ends by clips set onto sleeve sections drawn together to form plait-like strings, in which a suspension loop is attached to one of the plaits adjacent the clip. It further relates to a method for attaching a suspension loop to a tubular sleeve drawn together to form a plait or braid-like string and a device suitable therefor.
It is known to equip sausages sealed at their ends by clips with a suspension loop in such a way that during the sealing process a prepared loop is placed into one of the clips and when it is pressed around the string of tubular sleeves it is attached to the clip and therefore to the string of tubular sleeves. Attaching the suspension loop to the clip leads to problems in particular if the tubular sleeve has to be moistened before filling, which is especially the case for certain types of sausage. The tubular sleeve absorbs water and thereby increases the volume of the string of tubular sleeves around which the clip is pressed. On subsequent treatments of the suspended portion pack (in the case of sausage possibly boiling, smoking, etc.) the water then escapes from the string of tubular sleeves, thus reducing the closing pressure of the clip. This is not usually a problem for the pack closure, but it has happened that—in the case of certain tubular sleeve materials—such as large and heavy portions hanging on the suspension loop may pull the string of tubular sleeves out of the clip and the portion pack falls off.
It is further known from DE 25 05 672 A1 to form a suspension loop from supplied binding twine and to fasten it to the string of tubular sleeves in the way initially indicated behind the clip, in other words between it and the actual sausage, by so-called tying off with a knot customary for the purpose. This method of attaching the suspension loop is also unable to prevent the clip being stripped off and carried along during drying of the tubular sleeve in the course of treatment procedures subsequent to the filling process, because the frictional engagement of the knot with the string of tubular sleeves is reduced.
The invention solves the problem depicted in that the attachment consists of a throttle knot or twist knot, encompassing the string with a circumferentially closed suspension loop. In contrast to a tying-off knot, the twist knot, also designated as a “clamping knot”, automatically adjusts to the changing volume, and therefore the diameter of the packaging string, wherein the frictional engagement between the twist knot and the string, which determines the security of the attachment, becomes greater the heavier the pack hanging on the suspension loop is; the frictional engagement therefore also adjusts automatically to the requisite retention force.
The formation of clamping knots is widely known per se. In connection with sausage production, for example, in DE 1 507 943 A1 (U.S. Pat. No. 3,331,623), a clamping knot for fixing the thread ends while tying off the string can be seen, whereby the knot is prevented from coming undone by friction; the simultaneously formed loop can indeed be used to suspend the sausage, but is not attached to the string by a twist knot and is not therefore pulled tighter as the loading increases.
EP 0 719 707 A1 describes a binding machine for tying off flexible containers by means of a lacing cord by forming a clamping knot, which is not part of a closed suspension loop, however, and therefore also does not form a twist knot which is subject to the tensile stress of the suspended weight.
It is of particular significance that the type of loop fitting according to the invention, by using a circumferentially closed suspension loop, allows it to be attached in the course of the filling operation of a filling and sealing machine without interruption, because the necessary steps of the attaching procedure can be integrated into the sealing sequence after the previous tubular sleeve has been filled. Accordingly the method according to the invention for attaching a suspension loop to a tubular sleeve gathered to form a plait-like string, in particular a sausage sleeve, exists in that the loop closed in the form of a rectangle clamped in an elongated narrow shape is guided tangentially to the string of tubular sleeves, then the loop is gripped through near a first rectangular end out of the tangential plane on a path concentric to the axis of the tube and from the side of the string opposite the tangential plane the loop is taken hold of at the other, second rectangular end, whereupon this second loop end is pulled through the loop near its first rectangular end, while maintaining the clamping, and the thus formed twist knot is pulled tight.
Suspension loops circumferentially closed by appropriate pre-fabrication are known per se, for example from DE 32 44 775 A1 (U.S. Pat. No. 6,390,912) and DE 198 15 574 A1. However, attaching them to a string of sausages has so far been done with the aid of a clip, as initially described.
A device for attaching a suspension loop to a tubular sleeve drawn together to form a plait-like string is distinguished in that arranged on a mount are a stationary two-pronged holding fork and a two-pronged clamping fork, movable relative to one another and perpendicular to the plane of its prongs, and a curved looping finger attached on one side and swivelable over a partial circle,
wherein the prongs of both forks are essentially perpendicular to a plane connecting the forks and can clamp between them the circumferentially closed suspension loop in the form of an elongated, narrow rectangle, which extends tangentially to the string with both longitudinal sides at the start of an attachment cycle,
and wherein the looping finger has a hooked tip, which during its swiveling movement, moves out of a neutral position on the side of the rectangular loop opposite the string through the rectangular loop near its first rectangular end held by the clamping fork around the string to the other (second) rectangular end, releases this from the holding fork and on swiveling back around the string and through the suspension loop carries it along on the first rectangular end, thus creating a (throttling) twist knot which fixes the suspension loop to the string.
Preferred configurations can be seen in the subordinate claims relating to this device claim.